November 6 Mon 13:30-15:00 Solar and Space Plasma Seminar hybrid; Subaru Building / Insei Seminar Room or Zoom
November 7 Tue 9:00-12:00
SOKENDAI Doctoral Thesis Preliminary Evaluation 総研大博士学位論文予備審査会
Lecture Room and Zoom&Large Seminar Room and Zoom
November 7 Tue 10:00-11:30 太陽系小天体セミナー zoom
November 8 Wed 10:30-12:00 SOKENDAI Colloquium Large Seminar Room in Subaru Building and Zoom
November 10 Fri 16:00-17:00 NAOJ Seminar Zoom/Large Seminar Room(hybrid)
詳細は下記からご覧ください。
=============== November 6 Mon===============
Campus： Mitaka
Seminar： Solar and Space Plasma Seminar
Regularly Scheduled/Sporadic： Scheduled
Date and time：6th November (Mon), 13:30-15:00
Place： hybrid; Subaru Building / Insei Seminar Room or Zoom
Speaker：Brigitte Schmieder
Affiliation：Observatoire de Paris, LESIA, France
Title：Solar jets observed by IRIS and high spatial resolution ground-based telescopes
Abstract：Solar jets have been observed over a large range of temperatures and wavelengths, from Hα for more than 50 years, to X-rays since the launch of the Yohkoh satellite in 1991. Several characteristics have been derived about their velocities, their rates of occurrence, and their relationship with CMEs. However, the initiation mechanism of jets, e.g. emerging flux, flux cancellation, or twist, is still debated. The high spatial resolution of IRIS and ground-based telescopes (SST,GST) allows us to make a step forward in understanding the relationship of cool and hot jets. Combining IRIS data with vector magnetograms we were able to study the magnetic environment favorable for the occurrence of jets. We searched for possible sites of reconnection by analyzing the magnetic topology.
We found that the magnetic reconnection site can be located at a null point in the corona as well as in a bald patch region forming a current sheet. The IRIS spectra provide evidence of bilateral flows at the reconnection site, due to a transfer of twist from a flux rope to the jet. We detected the presence of cool plasma and hot plasma during the jet formation, including ejections of blobs with speeds reaching super Alfvénic flows of the order of 300 km/s.
Facilitator
-Name：Takayoshi oba
Comment：in English
=============== November 7 Tue===============
Campus：Mitaka
Seminar：SOKENDAI Doctoral Thesis Preliminary Evaluation 総研大博士学位論文予備審査会
Regularly Scheduled/Sporadic：Sporadic
Date and time：November 7, 2023 9:00～12:00
Place 1：Lecture Room and Zoom
Speaker：
9:00-9:40 Raiga Kashiwagi
Title：Instability and Evolution of Shocked Clouds Formed by Collisions between Filamentary Molecular Clouds
Speaker：
10:00-10:40 Yui Kasagi
Title：Unveiling Atmospheric Features of Faint Substellar Companions from High-Resolution Near-Infrared Spectra
Speaker：
11:00-11:40 Takaho Masai
Title：A Study on the Design of Receiver Optics and Waveguide Components Towards High-Performance (Sub)millimeter Wave Multibeam Receivers
Place 2：Large Seminar Room and Zoom
Speaker：
9:00-9:40 Rikuto Omae
Title：Probing the Magnetic Fields of Distant Galaxies to Unravel the Evolution of Galactic Magnetic Fields
Speaker：
10:00-10:40 Yuta Tashima
Title：Elucidation of Galactic Magnetic Field Structure by Pseudo-Observation Focusing on Depolarization
Facilitator
-Name：Nozomu Tominaga, Hideyuki Kobayashi, Natsuko Fujii (Graduate Student Affairs Unit)
=============== November 7 Tue==============
キャンパス：三鷹
セミナー名：太陽系小天体セミナー
定例・臨時の別：定例
日時：11月7日（火曜日）10時00分～11時30分
場所：zoom
講演者：佐藤幹哉
世話人の連絡先
名前：渡部潤一
備考：テレビ会議またはスカイプによる参加も可
=============== November 8 Wed==============
Campus：Mitaka
Seminar：SOKENDAI Colloquium
Regularly Scheduled/Sporadic：Regular
Date and time：November 8, 2023 10:30-12:00
Place：Large Seminar Room in Subaru Building and Zoom
Speaker: Shunsuke Sasaki
Affiliation: SOKENDAI 4th year (D2) (Supervisor: Tomoya Takiwaki, Mami Machida, Takashi Moriya)
Title: Developing “1D+” simulation of core-collapse supernovae
Speaker: Raiga Kashiwagi
Affiliation: SOKENDAI 5th year (D3) (Supervisor: Kazunari Iwasaki, Tomoya Takiwaki, Doris Arzoumanian)
Title: Instability and Evolution of Shocked Clouds Formed by Collisions between Filamentary Molecular Clouds
Facilitator
-Name：Matsuda, Graduate Student Affairs Unit
=============== November 10 Fri==============
Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Regular
Date and time：November 10, 2023 16:00-17:00
Place：Zoom/Large Seminar Room (hybrid)
Speaker：Prof,Yasuhito Sekine
Affiliation：Earth-Life Science Institute
Title：Detection of phosphate in Enceladus’ ocean and comparative chemical evolution in the Solar System
Abstract:
Planetary habitability can be defined as a planetary-scale system that can develop and sustain ingredients of life—liquid water, organics, and energy—over geological time. In this regard, Enceladus possesses a habitable world beneath the icy shell. This moon has a global subsurface ocean interacting with a rocky core, and a wide variety of organic matter and chemical energy supported by hydrothermal activities are available. Among the major bioessential elements for Earth’s life, phosphorus (P) is usually the least abundant in natural aqueous systems and has been a limiting nutrient of primary productivity over Earth’s history. It has been unknown whether this essential element is available in Enceladus. Here we report the discovery of phosphate in ice grains emitted by Enceladus based on the analysis by Cassini’s Cosmic Dust Analyser. Our observational results are evidence that phosphorus is readily available in Enceladus’ ocean, with anomalously high concentrations–at least 100 times higher than Earth’s oceans. To understand the causative mechanism of the enrichment of phosphate, we performed hydrothermal experiments and geochemical modeling. We find that alkaline (pH ~10) and carbonate-rich aqueous environments are essential for the phosphate enrichment, where calcium phosphate minerals are thermodynamically unstable compared to calcium carbonate minerals. Such alkaline carbonate-rich aqueous environments are commonly achieved in icy ocean worlds beyond the CO2 snowline of the Solar System. Phosphate could have been also enriched in similar alkaline carbonate-rich aqueous environments on early Earth, where earliest life on Earth might have utilized phosphorus as components of its building materials.
Facilitator
-Name：Okamoto, Takenori